Direct communication is one of the main features of device-to-device (D2D) services. To facilitate D2D communication, both a transmitting device and a receiving device must have a common understanding of the radio resources to be used. Several methods could be used to allocate resources for D2D communication. For example, a controlling node, such as a wireless controller (e.g., a base station, a NodeB, an evolved NodeB (eNodeB), a base transceiver station (BTS), or an access point) may allocate radio resources to a transmitting device, and inform receiving devices of this allocation. Typically both transmitting and receiving devices would get information about the D2D resource allocation from respective control messages transmitted over an air interface protocol, such as LTE.
In the case of a communication system that includes many wireless controllers, the transmitting device may be controlled by one wireless controller while one or more receiving devices may be controlled by another wireless controller. In this scenario, it may be difficult for the controller that assigned the radio resources to the transmitting device to also communicate this allocation to all potential receiving devices for the D2D communication.
If a potential receiving device is controlled by the same wireless controller as the transmitting device, then the controller can directly communicate the allocated D2D resources to this receiving device. However, if the potential receiving device is controlled by another wireless controller, then it is unlikely that the first wireless controller can communicate directly with such a receiving device.